Roof drilling and bolting is a well known process for maintaining the integrity of mine roofs; in other words for preventing the collapse of the roof. Special machines have been developed for assisting in the roof drilling and bolting process (hereafter the "roof bolting" process). See, for example, U.S. Pat. Nos. 3,252,525; 3,375,880; 3,768,574; 3,842,610; 3,951,215; 4,050,259; and 4,079,792. In a typical roof bolting process, a bore is drilled upwardly into the roof a distance depending upon the nature of the overburden. Thereafter, a self-anchoring bolt is turned up into the bore to compress the roof (ceiling) adjacent the bore and the bolt. In some practices, the bolt is secured in the bore with epoxy cement. The applicants' roof bolting device differs from those disclosed in the prior art in having a unique configuration which enables two driller operators to always remain under protective canopies while tramming into position and drilling or bolting. Further, the unique configuration will encourage the operators to use the machine exactly as intended. Prior machines, while in theory designed for safety, often fail to make it more convenient and comfortable for the operators to remain under a protective canopy at all times.
In a mine passageway of typical width, say 15 to 20 feet, it is desirable to place roof bolts transversely spaced across the passage to within about 2 to 4 feet of the side walls. Most efficient roof bolting will take place with a minimum of chassis positioning and repositioning. Applicants provide a roof bolting device that enables two operators to work opposite sides of a mined passageway from cabs transversely positionable independently of one another. Hence, the chassis which is, say 9 feet wide, may be moved down the center of the passageway and, without further repositioning roof bolts can be placed out to 6.5 feet from the center line of the chassis (also the center line of the passageway) on both sides.
It is an advantage of the device set forth herein that two canopy covered cabs are independently movable transversely of the center line of the chassis. Each cab has its own controls for cab positioning relative to the chassis and each cab has its own controls for positioning the associated drill pod relative to the cab. Each cab can be simultaneously extended to its outer transverse position. When the cabs are retracted to their innermost position no transverse beams or the like extend transversely outwardly of the chassis. There is no need for a plurality of stabilizing jacks to support the cabs relative to the floor during operation as the cabs may be rested upon the floor in any position and the tower for raising the drill pod is designed to automatically drop to engage the floor before the drill steel engages the mine roof.
It is a requirement of the mine safety laws that in most instances temporary roof supports must be positioned in front of a roof drilling and bolting device before the actual drilling and bolting process commences. Until recently, it has been necessary for miners to enter under the unbolted roof to place temporary roof support jacks. Some recent roof bolting devices propose extending the canopy generally positioned over the operator to engage the roof. This, of course, necessitates the repositioning of the roof support each time the operator's position is changed.
It is an advantage of the device set forth herein that a temporary roof support is carried by the chassis on a boom extending forwardly of the chassis and once the temporary roof support is positioned, it does not require repositioning during the repositioning of operator cabs transversely of the chassis.